Cellular systems are widely deployed by wireless carriers over a wide geographic area. Various techniques are used for covering hard-to-reach places, for example, repeats, cell-splits etc. These techniques are often unable to provide sufficient coverage to local communication devices.
Femtocells may be deployed to provide licensed spectrum cellular systems within tightly constrained geographic areas. Femtocells normally cover a space as small as a room within a building, a small home and/or a business location. Femtocells are typically designed to provide service areas of 100-1000 square meters, while macrocells normally cover areas on the order of 10-100 square kilometers, and microcells cover 1-10 square kilometers, and picocells cover 10,000-100,000 square meters.
Licensed-spectrum femtocells are usually designed to utilize a similar air-interface as an external macro-cell network so that the vast majority of devices can be used without any change. Femtocells operate according to a typical base-station-to-handset infrastructure.
Femtocell network deployments are not significantly structured or preplanned. Rather, these networks often comprise a plurality of ad-hoc femtocell deployments. The simple femtocell configuration allows the femtocell networks to adapt to meet the requirements of many different deployment environments. For example, some networks might scale to one million femtocells, any of which might enter or leave the network at any time.
In some networks, a femtocell network operator, such as, a business owner, might operate an entire network of femtocells for a selected group. For example, an office building might deploy a femtocell network to provide mobile telephone access to the employees. In these environments, many businesses might desire to forgo the use of typical landline phones or VOIP phones in favor of a mobile Internet business telephone network that allows their employees to use their mobile devices as replacements for expensive phone lines and Internet services. However, to replace a landline or VOIP system, a private branch exchange (PBX) that provides support for VOIP and/or landline PBXs is typically desired. However, because of the dynamic nature of a femtocell network it is challenging to integrate different network communication infrastructures, such as, VOIP communications, PBX communications, mobile station to landline and vice-versa, etc. Specific signaling and procedural guidelines must be adhered to when integrating communication systems with femtocells.